In an installation duct of the type named above and known from the German patent 24, 58 311, the retaining strip and the capping are provided with upper and lower connectors, which form a snap fastener in that a latch clasp of the capping is secured at an upper abutment and, after that, a lower catch at the capping is swung into a corresponding counter-formation, in which it is latched under pressure. The cable or pipe duct, so formed and closed at the periphery, has uniform internal dimensions for accommodating even very different pipelines and with that, a uniform appearance.